Tasam anaditvam ca asisah nityatvat
In sutra 4.9, Patanjali mentions about subconscious imprints (samskara) and memory. This sutra continues to explain that these samskaras and memories have existed eternally, as the desire to live is eternal.
Desire is an earnest longing for attaining some object or goal. All living beings have desires in order to perpetuate their existence. When a desire arises, there is a sort of stirring inside the person, he started to make plans and act accordingly. Thus, desire is the driving force behind all actions. It is like the fuel in the car, without fuel, the car will not move.
Desire is the root of other emotions. When a desire is fulfilled, one feels proud. This may lead to greed, which is going to cause serious problems in life. When a desire is not fulfilled, one feel upset, angry, etc.; this is also problematic.
It is not possible and not practical to “kill” all the desires within us and around us, because desires are eternal. Then how to minimize the effect of desires in our life? Recall the last time when we desired for something. The reason why we ran after it, is we thought we would be happy by attaining it. But think about this: a woman is never attractive to someone who does not desire for her; only the man who desires for her feels happy to be with her. Thus, the woman herself does not equal to “happiness”. Back to our previous example, no matter what we are chasing after, we have mistaken it for “happiness”, by associating ourselves with our desires. If we keep thinking in this way, we will never be able to realize our cheerful nature and become free. In yoga practice, we do not suggest to “kill the desires” or “kill the mind”, but to live with it. As Lord Krishna says in Bhagavad Gita (Chapter 5 Verse 23), he who before leaving this body, right here, is able to endure the impetus rising from desire and action, he is harmonized, he is a happy man.
By practicing asana, pranayama, and meditation, practitioner will gradually become discriminative. He will see the whole world as it is, accept the existence of desires, mind and ego, and make them at rest.